Abstract: The circular electron positron collider (CEPC) is a future large collider facility proposed by the high energy physics community in China. It will serve as a Higgs boson factory, and produce large quantities of Z and W bosons, so it will be able to perform precise measurements of the Higgs boson properties, weak electromagnetic force physics, flavor physics, and quantum chromodynamics. Through these high-precision tests, the CEPC could explore new fundamental principles underlying the Standard Model particle physics. Dedicated studies on the potential of CEPC and the critical technologies involved have already been performed. In November 2018, the Conceptual Design Report, a preliminary blueprint of CEPC was published; its successful completion means that the project has now entered the phase of engineering design.The physics potential and progress of the R&D of CEPC will be reviewed in this paper.